MSSM corrections to the top–antitop quark forward–backward asymmetry at the Tevatron

Abstract

We study the effects of the complete supersymmetric QCD and electroweak one-loop corrections to the \(t\bar{t}\) forward–backward asymmetry at the Fermilab Tevatron \(p\bar{p}\) collider. We work in the complex Minimal Supersymmetric Standard Model (MSSM), only restricted by the condition of minimal flavor violation (MFV). We perform a comprehensive scan over the relevant parameter space of the complex MFV–MSSM and determine the maximal possible contributions of these MSSM loop corrections to the forward–backward asymmetry in the \(t\bar{t}\) center-of-mass frame. We find that the SUSY loop-induced asymmetry at the Tevatron with \(M_{t\bar{t}}>450~\mbox{GeV}\) can be at most +2 % for very light SUSY particles, i.e. for \(m_{\tilde{t}_{1}} <100~\mbox{GeV}\) and \(m_{\min} = \mathrm{Min}\{ m_{\tilde{g}},m_{\tilde{u}_{1,2}},m_{\tilde{d}_{1,2}}\}<100~\mbox{GeV}\), which reduces to 0.1 % for gluino and squark masses in the range 850 GeV–1000 GeV and a light top squark of \(m_{\tilde{t}_{1}}=200~\mbox{GeV}\).